Conventional follow-up systems respond to position errors of a control system in a linear manner such that the control command is proportional to the position error. In some conventional follow-up systems, the control system continually commands the follow-up system to respond to even small positional errors that are well within the dynamic range of the control system. In other conventional follow-up systems, the follow-up system may allow the control system to operate within a dynamic range, however large initial step commands are provided to the follow-up system when the dynamic range is exceeded. Large step commands are undesirable, especially in sensitive electro-optical and mechanical systems. For example, tactical airborne systems may utilize an inner yaw gimbal and one or more outer roll gimbals for laser designation, targeting or positioning. The inner gimbal may be a fine gimbal and may be part of a control system and the outer gimbal may be a coarse gimbal and may be part of the follow-up system. In operation, the outer gimbal may have to continually roll to keep the yaw of the inner gimbal zeroed.
Thus there is a general need for a follow-up system and control method that allow a control system to operate within a dynamic range. There is also a general need for a system and control method that does not command a follow-up system with large step functions. There is also a need for an improved laser designating and/or targeting system suitable for use in tactical airborne systems.